1. Field of the Invention
The invention relates generally to automatic power control and more particularly to remote control methods and devices to operate computer systems.
2. Description Of the Prior Art
Appliances, such as computers and their printers, can perform useful functions when left unattended at remote sites. It therefore often becomes necessary to remotely control the power on/off and functioning of such appliances, e.g., by phone. But such control can be confused by the presence of manual, local on/off switches on the appliances themselves or override buttons provided on the remote control device. The confusion arises because the remote control is conventionally not able to sense the operation or status of such manual or override controls.
Various kinds of remote controlled power switches have appeared on the personal computer (PC) after market. One such device is a telephone activated power control unit marketed in the United States as POWER-ON by Server Technology (Santa Clara, Calif.). It allows a PC, equipped with a standard telephone line and modem, to power-on/off a remote appliance. Using bundled communications software the PC can operate the remote PC, run its programs, transfer data files, and use a printer.
U.S. Pat. No. 4,647,721, issued to Busam, et al., describes a telephone activated power controller having an electrical power inlet and a number of outlets for various appliances, such as a computer. A detector senses a ring condition on a standard telephone line and goes off-hook while connecting inlet power to its outlets. A remote control unit allows the computer to keep the power on after hang-up (on-hook) or manual power-off. A status sensor can tell the computer if the device has been turned on manually or remotely. An inhibit circuit can prevent the device from responding to a telephone ring or off-hook condition. The controller also has surge protection on the power outlets.
A device called POWERKEY is marketed for use with the Apple Macintosh PC. This device reportedly can turn a system on and off, and it can execute keyboard macros at present times, for applications such as unattended backups or telecommunications file transfers. A "cdev" program enables daily, weekday, weekly, monthly, and unique events to be scheduled. The Macintosh can be turned on with a phone call using a POWERKEY remote device. Software such as TIMBUKTU REMOTE or CARBON COPY MAC can allow the computer to be operated from a remote location as if the operator were actually in front of the computer, and not one connected to it.
Another device called PHONEBOOT is sold by Cybex Corporation (Huntsville, Ala.) allows a user to boot computers, peripherals, and other appliances from a remote location using a telephone, while providing built-in password protection. The device has six 120 VAC outlets, surge protection, a phone plug, a modem plug, and a power cord. It works with Hayes compatible modems and TOUCH TONE (DTMF) telephones. There are three modes of operation: remote enable, local on, and master off. In remote enable, the device monitors an incoming phone line for a call. After eight rings, the call is answered and the caller is given a prompt tone and a three digit security code must be entered. The code can come in via TOUCH TONE phone or by modem. If the code is accepted, the power outlets are turned on. If a modem is attached, it must provide an answer back tone to the caller and establish a communications channel. Power is left on for 18 minutes after hanging up. Yet another device is the TELESWITCH by EKD (Selden, N.Y.) which uses a four digit security code, a local ring circuit for a modem after power-up, and automatic modem transfer to phone line after modem answers local ring. It is advertised to work with host/remote software such as pcANYWHERE (Dynamic Microprocessor Associates). The device allows a user to disconnect during a call to save on phone charges while leaving the computer on. A later call-back can shut the power down.
Other units with more-or-less the same features described above are the "Remote PowerOnOff Control" by L-Tech Associates (Oak Lawn, Ill.), the INTELE-STRIP 800 from ALM (California), and the Lead Operated Relay (LOR-II) GS-SW701A by Black Box Catalog.
The prior art does not provide a device or method for the sensing of whether an appliance that is off can be automatically turned-on.